Design For Silence

In the quest for quiet operation demanded by competitive clients, Hansen has studied the factors that influence the noise produced from a gearbox in operation. Accuracy under load is the key to low noise. To ensure this goal is obtained, Hansen developed the following design objectives.

• Accuracy of machining.
  The quality and accuracy of the gearing determines the noise behavior. Grinding of all gears to manufacturing tolerances is thus standard procedure. Beyond a given degree of manufacturing accuracy, deflections take over the noise production.

• Stiffness in design.
  The deflection of long overhung pinion shafts are minimized by designing the housings for shorter shafts. This simultaneously increases the stiffness of the housing improving the noise damping.

• Gear optimization.
  Gearboxes are subjected to a variety of loads and the gear and shaft deflections are proportional to these loads. Combined with the stiffness of the gearbox geometry the gears are constructed to deflect to perfection using advanced design methods. This allows for a larger range of quiet operation of the unit.

• Housing design.
  Apart from design for shaft lengths the housing is also designed to cope well with introduced external loads from the mounts and operating environment. Efficient dissipation of these forces allows for quieter operation due to greater accuracy under load, and deflections of the housing not influencing the meshing of the gears.

Through the years of development a reduction of more than 10dBA has been achieved since the mid eighties.